Internal-combustion engine



Aug. 13, 1929. E. SOKAL INTERNAL COMBUSTION ENGINE Filed May 1927 INVENIVTOR.

a ATTORNEYS.

UNITED STATES PATENTOFFICE.

EDWARD SOKAL, OF

RATION, OF NEW YORK, N

NEW YORK, N.

Y., ASSIGNOR TO AMERICAN KATALITE CORPO' Y., A CORPORATION OF DELAWARE.

INTERNAL-COMBUSTION ENGINE.

Application filed May 5,1927. Serial No..188,893. I

This invention relates to internal combustion engines, to correlated improvements and discoveries whereby and wherewith the operation thereof is enhanced, and more particularly to the prevention of detonation in the combustion chamber thereof.

An object of the invention is directed to the provision in an internal combustion en-.

gine of an improved detonation counteractant.

' Another object is to provide an improved method of permanently preventingv detonation in an internal combustion engine.

A further object is t 0 provide an improved coating composition which may be affixed to the walls of the combustion chamber of an internal combustion engine to prevent detonation therein.

In my co-pending application, Serial No. 42,583, filed July 9, 1925, patented June 7,

1927, No. 1,631,702, I tendency toward combustion engine,

nounced tendency thereto be counteracted by fixedly sion engines, may

have shown that the detonation in an internal particularly the proin high compresdisposing within the combustion chamber of the engine a material capable of undergoing a reversible endothermic, i. e., heat-absorbing-,change within the range of temperatures and amid the other conditions existent in the engine during operation, by means of which a cooling effect is exerted upon the gaseous mixture within the chamber with a resultant counteraction of detonation.

\Vhile itis well recognized that detonation of the gaseous mixture within a combustion chamber can be counteracted by cooling the mixture, no theory of this phenomenon ccpted. knocking, in internal mainly due to a down of the unburned offered in explanation has been universally ac- It is vmy view that detonation, or

combustion engines, is

decomposition or breaking fuel, or in other Words,

I to the dissociation of'the larger molecules of the fuel under the influence of heat and pressure into a greater number of smaller mole-' whereby there is caused a sudden rise This rise of pressure may not cules, of pressure.

be indicative'of tlie true pressure condition within the whole ody of the fuel-air mixture, but is rather in the nature of a localized impact. This view is lowinggconsiderations tendency of various supported by the fol- First, thedetonating fuels is practically a "a very short period of time, 'is ,an equally rapid t ive impacts.

function of their thermal stability, for example, the tendency to detonate decreases in the following order: Kerosene, ordinary gasoline, aromatic gasoline, benzol, alcohol and hydrogen, and the thermal'stabilit in creases in the same order. Second, the mdicator diagram of detonating engines. shows a [very rapid rise of pressure Whichlast-s only -hence they manifest themselves as destruc- Third, detonation is accom- H deposition of carbon panied by lost power,

to the water jacket,

and great loss of heat which loss of power and deposition of carbon may be considered natural results from the decomposition of the fuel, and the loss of heat to the water jacket is probably due to radiation caused by glowing particles of carbon and to the impacts. Fourth, it has been shown that various factors which cause an increase in the rapidity and make the combustion more complete have a rather pronounced effect in counteracting detonation. This would seem to follow as an indirect result of the fact that the smaller each of combustion 7 molecules of the fuel cannot simultaneously undergo a reaction of combustion and of decomposition. a Y

In my patent above referred to, I have disclosed as an exemplification of a detonation countcractant suitable for use in accordance with the invention, a material, the meltin point of which is such as to render it capa le of undergoing a reversible change from solid to liquid state under the conditions of engine operation, and I have particularly suggested the use of lead, antimony and tellurium.

The present application is a continuation in part of my co-pending application, Serial No. 142,247 filed October 18, 1926, patented J unc 7, 1927, No. 1,631,703, wherein it is disclosed that an especially effective detonation counteract-ant forsuch use is a non-fugitive, preferably solid, material which is capable under the conditions of engine operation of change at the higher range of temperatures existent within the combustion chamber of the enginein' which it is employed so as to be converted into a difi'erentnon-fugitive, preferably solid, chemical material, which latter material is capable underthe conditions of engine operation of undergoing, at the lower range of temperatures existent within the combustion chamber, a heat-1e leasing (exothermic) change so as to restore itself for further heat-absorbing action. It will be realized from the above that I use a material which undergoes a reversible chemical change under operating conditions, and that the original substance disposed within the chamber may contain a material appearing on either side of the equation expressing the change, or both. with a view to simplicity of definition, the term chemically endothermically reactive material, as hereinafter understood to designate either a material falling withinthe definition of my'improved detonation counteractant given above, or a substance which is convertible into such material under the conditions of engine operation. It willbe appreciated in this connection that since the invention relates to internal combustion engines, the term chemically endothermically reactive material as employed hereinafter includesonly such substances as will undergo the desired reactions within the range of temperatures and under the other conditions found within the combustion chamber of the engine'in which it is employed.

A chemically endothermically reactive material is particularly advantageous for use as, a detonation counteractant within the combustion chamber of an internal combustion engine because of the marked l1eat absorption during the endothermic reaction, with the consequent high cooling effect upon the gaseous mixture. Furthermore, when there is employed a solid material which is converted into another solid material under the conditions contemplated by the invention, a further advantage is to be found in the elimination of any possibility oflthe loss of the detonation counteractant by the escape of a material which has been converted into a fluid state.

In practice, a material capable of undergoinga reversible chemical change which is endothermic during the power stroke, when the temperatures within the chamber are the highest and the consequent tendency toward detonation is the greatest, is fixedly disposed within the combustion chamber of an internal combustion engine, preferably in the form of, oras an ingredient of, a coating applied to certain portions of the walls of said chamber. This coating is especially effective when applied to certain of those portions of the chamber walls which are hottest Accordingly,

employed, is to be,

ing engine operation, and that this carbonate is readily formed when a coating containing powdered metallic copper is present on the walls of the combustion chamber. Moreover, the known facts relating to the reactivity of. these two materials suggest that the reversible reaction occurring within the chamber during operation may be expressed by the equation:

Cu(OH)z.CuCo; A Si, .011 mo 00, o, A,

wherein the symbols A and A indicate absorption and release of heat, respectively.

It is, however, to be understood that this suggestion is based partly on theoretical con- It has been siderations, and that some other equationmay better express the actual effect-Ive reversible reaction which occurs. The known facts are that, under the conditions of engine operation, basic copper carbonate isreadily formed on the surface of a coating containing copper powdered; and that when either powdered metallic copper or powdered basic copper carbonate is utilized in accordance with the invention, a marked decrease in detonation is secured. It will be appreciated, however, that the invention is not so limited as to exclude other copper carbonates which may act endothermically, or which may be convertible into a carbonate "which so acts, or toexclude other copper-containing materials besides metallic copper (such, possibly as the oxides or hydroxides of copper) which are convertible into a coppercontaining material which. acts endothermically under engine operating conditions.

In view of the foregoing, it Wlll be understood that wherever, for the sake of uniformity of expression'inthis and applicants copending application, the term coppercontainingsubstance of. the carbonate-oxide type is employed below, that the term is intended to refer either to an endothermicallyreactive copper carbonate, or to any other material (including metallic copper) which is convertible into such carbonate under the conditions contemplated by the invention.

The accompanying drawing is a partly sectional view exemplifying a form of the invention. In this exemplifieation a cylinder block 1, together with a high compression cylinder head' 2, )rovides a combustion provided a coating 9 which may also contain a relatively permanent chemically endothermically reactive material of the copper type in a finely divided condition.

It is to be noted that the chemical changes occurring during .ordinary operation probably take place only in the exposed surface layer of the detonation counteractant, and also thateven on this layer each molecule of the material is probably not converted under ordinary conditions, but that the reaction occurs merely in a proportion of the molecules su'fiicient to exert the required cooling effect or to restore the material for further heat absorption, as the case may be.

In'order properly to secure it in place, the improved detonation eounteractant may be applied to the desired portions of the chamber Walls in a finely divided condition and in admixture with a suitable binder,

such as a silicate. For example, an intimate mixture of powdered copper (or other chemicallyendothermically reactive material of the copper type) and a silicate binder in substantially equal proportions, or such other proportions as may be dictated by the conditions of the particular case, may be applied in the form of a coating on the exposed surface of the piston head, and/or such other portions of the walls as may be 'desired. The application may -,be accomplished by cleanlng the desired surface area, coating such area with the detonation counteractant, and baking or setting. This procedure may be repeated, if desired, until several coats have been applied. Electrolyticcopper is especially desirable for such use because .of its marked activity. Theamount of the improved.detonation counteractant to be applied in a particular type of engine may be readily determined by suitable tests indicating the proper surface area to be coated in order to obtain eflicient operation.

It has also been found that particularly satisfactory results are obtained when the initial coating contains metallic copper and lith'arge' -In fact, comparative tests have demonstrated that better results are secured by the use of such-a mixture than by the use of either copper (or basic copper carbonate) or litharge (or lead carbonate) alone. This may be because of a cumulative effect of the two types of materials, due, possibly to the fact. that they are most effective at slightly different temperatures; or it may be because of some catalytimeflect, such, possibly, as a catalytic effect of the copper on a lead carbonate-litharge reaction, or vice verse. Experimental evidence indicates that the latter is probably the case, and that the increase in anti-dctonating effect is probably. due to the catalytic action of the copper on the re-. actions undergone by the litliarge or other chemically endothermically reactive ma-. terial.

At'the present time the phenomenon of detonation, or knocking, during the operation of internal combustion engines is of much interest because, other conditions being equal, it is more pronounced with engines of high compression ratios. Accordingly, this tendency to detonate with a given fuel becomes practically a limiting factor for improvement in the thermal efficiency and power output through an increase in the compression ratio. This is particularly the case with the constantvolume cycle type of engine which is used almost exclusively in automobiles and in aeroplanes and also to a considerable extent in small marine and stationary engines.

v It is true that there are other limiting factors, such as loss in mechanical efficiency, which may offset the gain in "thermal efli: ciency after a certain increase in the compression ratio, but the limitation due to the injurious effects of detonation becomes operative before these other limiting factors exert their influence. Accordingly, it will be apparent that the present invention, because of the marked effectiveness of a chemically endothermically reactive material as a detonation counteractant, will permitthe designing of engines having a higher compression ratio than has heretofore been possible.

Among the other advantages arising through the utilization of the detonation counteractant, mention may be made of the following: lack of detonation or knocking,

lower fuel consumption, more'flexible operation of the engine, decrease in carbon deposition, and an increase in the thermal efficiency, particularly in connection 7 with the use of high compression engines.

It is, of course, to be understood that the invention does not contemplate the use of a material of such a nature that a compound appearing on either side of the equation expressing the reaction occurring within the chamber, has a known cracking effect or other property which would tend to overbalance the effective anti-detonating effect produced by heat absorption during the endothermi': reaction.

While the theory herein presented offers a basis' for an understanding of the manner in which the detonation counteractant may function, and while it is supported by known facts, it is to be understood, of course, that the operativeness and practicability of the invention is not dependent upon or limited in any way by the correctness of such theory.

Since certain changes may be made in the detonation counteractant above described, and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

Itis also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall thercbetween.

I claim: r

1. In an internal combustion engine, the combination with a combustion chamber of acoating disposed on certain of the walls of said chamber, said coating containing a relatively permanent detonation counteractant comprising a chemically endothermically reactive material of the copper type in a finely divided condition.

2. In an lnternal combustion engine, the

combination with a combustion chamber of a coating formed on certain of the walls of said chamber, said coating comprising a copper-containing substance of the carbonateoxide type in a finely divided condition.

3. In an internal combustion engine, the combination with a combustion chamber of a detonation counteractant fixedly disposed on certain of the walls of said chamber, said detonation counteraetant comprising powdered metallic copper.

4. In an internal combustion engine, the combination with a combustion chamber of a detonation counteractant fixedlydisposed on certain of the walls of said chamber, said detonation counteractant comprising basic copper carbonate in a finely divided condition.

5. In an internal combustion engine, the combination with a combustion chamber of a coating disposed on certain of the walls of said chamber, said coating comprising a substance of the copper type and a chemically endothermically reactive compound of another metal.

6. In an internal combustion engine, the combination with a combustion chamber of a coating disposed on certain of the walls of said chamber,said coating containing metal lic copper and litharge.

7. In an internal combustion engine, the combination with a combustion chamber of a coating disposed on certain of those portions of the walls of the chamber which are hottest under operating conditions, said coating containing a chemically endotherlnically reactive material of the copper type in a finely divided condition.

8. In an internal combustion engine, 11.

combustion chamber arranged for the reception of a gaseous mixture and fitted with a piston presenting an exposed surface to the gas in said chamber, said surface comprising active material of the copper type in a finely divided condition.

10. In an internal combustion engine, the

combination with a combustion chamber of a coatingdisposed on certain of the walls of said chamber, said coating comprising a relatively permanent chemically endothermically reactive material of the copper type in a finely divided condition, and a binder.

11. In an internal combustion engine, the combination with a combustion chamber of a coating comprising a copper-containing substance of the carbonate-oxide type in a finely divided condition and a silicate binder.

12. In an internal combustion'engine, the combination with a combustion chamber of a coating comprising metallic copper in a finely divided condition and-abinder.

13. In an internal combustion engine, the combination with a combustion chamber of a coating comprising basic copper carbonate in a finely divided condition and a binder.

14. A method of counteracting detonation of the successive fuel charges in the coinbustion chamber of an internal combustion engine, which comprises permanently exposing to such charges a chemically endothermically reactive material of the copper type in a finely. divided condition.

15. A method of counteracting detonation of the successive fuel charges in the combustion chamber of an internal combustion engine, which comprises forming an intimate admixture of a chemically endothermically reactive material of the copper type in a finely divided state and a silicate binder, and applying the resultant admixture to certain portions of the vwall of the combustion chamber of the engine.

16. A method of counteracting detonation of the successive fuel charges in the combustion chamber of an Internal combustion engine, which comprises applying a coating containing powdered metallic copper on cer-' tain portions of the Wall of the combustion chamber of the engine.

17. A method of counteracting detonation of the successive fuel charges in the combustion chamber of an internal combustion engine, which comprises applying to certain portions of the wall of the combustion chamber of the engine a coating containing metallie. copper and litharge 18. In an internal combustion engine, the combination with a combustion chamber, of a coating disposed on certain of the Walls of said chamber, said coating containing a chemically endothermically reactive material and a catalyst.

19. In an internal combustion engine, the

combination with a combustion chamber, of

a coating disposed on certain of the walls of said chamber, said coating containing a chemically endothermically reactive material and a 'atalyst comprising copper.

20. In an internal combustion engine, the combination with a combustion chamber, of a coating disposed on certain of the walls of said chamber, said coating containing a chemically endothermically reactive lead compound of the carbonate-oxide type and finely divided copper.

21. In an internal combustion engine, the combination with a combustion chamber of a coating disposed on certain of the walls of said chamber, said coating containing a relatively permanent detonation eounteractant comprising a chemically endothermically reactive lead compound in a finely divided state and a finely divided catalyst intimately admixed therewith. i

In testimony whereof I aflix my signature.

EDW'ARD SOKAL. 

